The present invention relates to vacuum cleaners, and more particularly, to a fill-up indication arrangement for use with a vacuum cleaner.
There are known in the art fill-up indication arrangements used in vacuum cleaners and operative for indication of the conditions that a filter bag contained in the vacuum cleaner is filled up. Such an arrangement is, for example, disclosed in a German Gebrauchsmuster publication DE-GM No. 69 20 047. The published disclosure describes a fill-up indication device which includes an up-and-down movable diaphragm which turns an indicator disc via a screw threadable into a nut positioned in the disc.
This otherwise satisfactory device fails, however, to reliably protect the movement translation means against contamination which penetrates the thread of screw-nut connection. A further disadvantage of the known arrangement is that in a switch-off condition of the device, when no under-pressure in the vacuum cleaner occurs, the indicator disc may inadvertently return to its jumping-off position (the indication is O.K.).